1. Field of the Invention
The invention relates to an illumination system, and in particular relates to an illumination system capable of changing a projection pattern by adjusting the positions of a reflector and a light source
2. Description of the Related Art
For a conventional optical design, a secondary lens and a reflector are used to generate a desired projection pattern. The secondary lens cannot change a projection pattern without affecting the emitting efficiency. Additionally, the reflector cannot concentrate an emitting angle of the light beam to the range of 10 to 45 degrees.
U.S. Pat. No. 4,037,036 discloses an optical design with the function of filtering UV/IR light reflected by a reflector.
U.S. Pat. No. 5,951,139 discloses a conventional operation lamp comprising a light source, a reflector and mirrors. The light from the light source is reflected by the reflector. The reflected light is reflected by the mirrors to generate a projection pattern. The mirrors are disposed around a circle with respect to the center of the operation lamp.
US patent publication No. 2006/0072313 discloses an optical design for light emitting diodes comprising a light source and a reflector. The reflector can be a lens or a hollow reflector.